The invention pertains to a payphone electronic coin validator.
In the United States the majority of the regional bell operating companies (RBOC""s) and independent telephone company payphone service providers utilize coin lines instead of business lines for their payphones. Coin lines include tip, ring and ground lines, and utilize a Central Office to provide collect and refund signaling, to provide coin line supervision for such operations as call start and call end, and to determine remote rate determination for other than local calls.
Payphones connected to coin lines are commonly known as xe2x80x9cDumbxe2x80x9d sets or xe2x80x9cSmartxe2x80x9d sets. A Dumb set has all telephone line functions performed at the Central Office, while a Smart set is characterized by an electronic chassis which performs some functions of the Dumb set as well as providing additional functions at the payphone station. An example of a Dumb set is a xe2x80x9c32Bxe2x80x9d telephone in wide use in xe2x80x9cWestern-Electric Companyxe2x80x9d-style housings.
When a call is initiated, a coin validator inside the payphone outputs signals to the payphone chassis as nickel, dime and quarter coins are accepted. In the case of a Smart or Dumb set connected to coin lines, the payphone chassis generates coin signal pulses for the Central Office according to telephone company specifications.
Mechanical coin validators were used in all payphones before the development of electronic coin acceptors, which offer improved coin validation and processing functions. Conventional electronic coin validators typically work in parallel with a line balancing circuit resident in the payphone chassis, and rely on the balancing circuit to release the telephone line for a period sufficient to enable the coin validator to work correctly. However, the chassis line balancing circuit in most Dumb sets was not designed to accommodate an electronic coin validator. Thus, in many cases the response time of the balancing circuit is too slow to keep up with the quickly fluctuating power demands of the electronic coin validator. Consequently, electronic coin validators have been designed to operate in an idle mode when the dumb payphone chassis is performing coin tone signaling in order to avoid corrupting the coin tones. In addition, a coin fall-through fault occurs when a consumer feeds coins into the payphone at a fast rate during an interval when the validator is not adequately powered so that some coins that should have been validated and credited to the total amount are not.
It would therefore be advantageous to provide an electronic coin validator for a payphone that is fully functional during all off-hook conditions including when the payphone chassis circuitry is generating coin tone signals.
An electronic coin validator for connection to a payphone chassis is presented. The validator includes a coin passageway having at least one coin sensor, power circuitry for connection to payphone chassis power lines and connected to the coin sensor, a validator line balance circuit connected to the power circuitry, at least one coin signal line for connection to the payphone chassis, at least one coin value buffer, and a control means. The control means processes signals from the sensor to validate coins, adjusts the count in the at least one coin value buffer when a coin is validated, and readjusts the count when corresponding coin credit signals are generated for transmission. The validator line balance circuit has an output for connection to the payphone chassis, and equalizes the loading on the telephone lines to minimize impedance fluctuations.
The invention advantageously permits normal electronic coin validator operations to occur while coin tones are being generated by the Dumb set payphone chassis for the Central Office, thus eliminating the idle mode of operation used by conventional systems. In an implementation, the electronic coin validator operates to buffer coin credit signals and to release those corresponding to lower denomination coins in priority over coin credit signals of higher denomination coins so that a consumer is confident that each inserted coin has been credited. In addition, the payphone electronic coin validator according to the invention operates to minimize coin tone distortion by minimizing line impedance fluctuations due to electronic coin validator current consumption variations. Further, coin fall-through faults are substantially eliminated because the invention ensures that the electronic coin validator has adequate power to validate and credit inserted coins.
Other uses and advantages of the invention will be apparent in view of the drawings and the detailed description.